Save: Missing plant for group &2 replen &3 material &4

What causes this issue?

Plant is missing on an assignment about to be saved.
Grouping WBS element: &V2&
Replenishment object: &V3&
Material: &V4&

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Possible cause is an incorrect BAdI implementation.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.